That's what I've done at YC for the last year or two. It's very efficient. I set aside a block of time, and founders book slots within it. I doubt we could fund 26 startups at once the way we used to do things, where each appointment had to be made individually.
You mentioned in your essay on this that you wrote a sign-up program for it. Just out of curiosity, did you use Arc? If not, why not? If it was written in Arc, I'd guess that it was much simpler than HN in terms of complexity.